Tuesday, 10 December 2013

Yet more evidence that MtoF and FtoM are not mirror-images, and that while saying "Trans women have female brains" captures the essence, and is useful as an initial step towards understanding, the reality is more complex than that. For that matter, cis women don't have female brains as such, yet men and women have statistical differences in neuro anatomy that correlate well with statistical differences in behaviour - such as sense of smell.

There is strong evidence of sex differences in mental rotation tasks.
Transsexualism is an extreme gender identity disorder in which
individuals seek cross-gender treatment to change their sex. The aim of
our study was to investigate if male-to-female (MF) and female-to-male
(FM) transsexuals receiving cross-sex hormonal treatment have different
patterns of cortical activation during a three-dimensional (3D) mental
rotation task. An fMRI study was performed using a 3-T scan in a sample
of 18 MF and 19 FM under chronic cross-sex hormonal treatment.
Twenty-three males and 19 females served as controls. The general
pattern of cerebral activation seen while visualizing the rotated and
non-rotated figures was similar for all four groups showing strong
occipito-parieto-frontal brain activation. However, compared to control
males, the activation of MF transsexuals during the task was lower in
the superior parietal lobe. Compared to control females, MF transsexuals
showed higher activation in orbital and right dorsolateral prefrontal
regions and lower activation in the left prefrontal gyrus. FM
transsexuals did not differ from either the MF transsexual or control
groups. Regression analyses between cerebral activation and the number
of months of hormonal treatment showed a significant negative
correlation in parietal, occipital and temporal regions in the MF
transsexuals. No significant correlations with time were seen in the FM
transsexuals. In conclusion, although we did not find a specific pattern
of cerebral activation in the FM transsexuals, we have identified a
specific pattern of cerebral activation during a mental 3D rotation task
in MF transsexuals under cross-sex hormonal treatment that differed
from control males in the parietal region and from control females in
the orbital prefrontal region. The hypoactivation in MF transsexuals in
the parietal region could be due to the hormonal treatment or could
reflect a priori cerebral differences between MF transsexual and control
subjects.

About Me

Actually, I am a Rocket Scientist.
Also hormonally odd (my blood has 46xy chromosomes anyway) and for most of my life, I looked male, and lived as one, trying to be the best Man a Gal could be. Anyway, in May 2005 that started changing naturally for reasons still unclear, and I'm now Zoe, not Alan : happier and more relaxed not to have to pretend any more.
UPDATE - reason now identified as the 3BHSD form of CAH.

Reviews

This blog, written by a rocket scientist, is a fascinating collection of information, both personal and scientific, regarding intersex, transsexualism and related psychosocial and psychosexual issues....It is erudite and heartfelt. Just read the posts about the passport issue. You won't know whether to laugh, weep or crawl into a ball and rock gently in a corner - an amazing person.- David---The reason I so appreciate bright, perceptive people - as opposed to ideologues whose intelligence does little to illuminate - is that they manage to both instruct and learn with a certain grace. Among such rarities in the transblogosphere is Zoe, whose direct speech and clear humanity always make her worth reading, even if one doesn’t always agree with her every conclusion.- Val---The following is a request for permission to archive your A.E.Brain blog site which we have wanted to do for several years...The Library has traditionally collected items in print, but it is also committed to preserving electronic publications of lasting cultural value....Since (1996) we have been identifying online publications and archiving those that we consider have national significance....We would like to include A.E.Brain blog site in the PANDORA Archive...-Australian National Library